Interlocking system for railroads



March 14, 1933. w. K. HOWE INTERLOCKING SYSTEM FOR RAILROAD-S Filed'July 31, 1950 2 Sheets-Sheet 1 M ATTORNEY March 14, 1933. w. K. HOWE INTERLOCKING SYSTEM FOR RAILROADS Filed July 31, 19.19 2 Sheets-Sheet 2 INVENTOR ATTORNEIY Patented Mar. 14, 1933 UNITED STATES rarer rice WINTHROP K. -HOWE, OF ROCHESTER, NEW YORK, TO GENERAL RAILVAY SIGNAL COMPANY, OF BGCHESTER, NEW YORK INTERLOCKING SYSTEM FOR RAILROADS Application filed July 31,

This invention relates to power interlocking systems for railroads, and more particularly to the control apparatus for such systems.

In accordance with this invention, generally stated, it is proposed to operate the con trol devices, commonly known as levers, of the typical and well-known interlocking system, as now employed for the control of switches and signals, by individual power units under the control of small levers or hand switches, conveniently arranged and grouped together for ready manipulation, instead of moving the control levers and the associated mechanical looking directly by hand.

The characteristic features, functions, and advantages of my improved system of power interlocking will be in part apparent to those skilled in the art, and in part explained, as the description progresses.

In the accompanying drawings Fig. 1 illustrates conventionally and diagrammatically in a simplified form one embodiment of the invention; and

Fig. 2 shows a modification.

Since these drawings have been prepared more with the idea of making it easy to understand the principles and nature of the invention, than for the purpose of showing specifically the construction and arrangement or" parts that would be employed in practice, some 01 the parts and circuits of a complete interlocking system, which are constructed and operated in accordance with well-known practice, have only been partially shown, or wholly omitted.

The invention contemplates the use of power-operated switch machines for moving and locking the points of the various switches in the plant; signals of any suitable type for governing train movements over the various switches in their diiierent positions; track circuits throughout the plant and line circuits for automatically controlling the signals; approach andrelease looking relays and circuits governed by the track circuits and provided with suitabletime releases; derails; and various other devices and accessories commonly employed in ac- 1930. Serial No. 472,051.

maybe operated and controlled, in accord ance with this invention, there is shown. in the accompanying drawings a single switch Sl V, provided w1th the usual detector track circuit having atrackrelay T (indicated conventionally by a dotted line), and provided with semi-automatic signals 1 and 2 for governing traffic in one directionover the switch;

The indications of these signals 1 and 2 are controlled in the usual way by signal relays 1H and 2H; and since the detail circuit connections for these signals are wellknown, they have been omitted and indicated conventionally by dotted lines.

The track switch SW is locked and 0perated by a suitable power-operated switch machine, shown conventionally and designated SM. This switch machine may be of any suitable type; and its construction, operation and method of control need not have any particular form to conform with the principles and mode ofoperation of the present invention. One type ofelectricallyoperated switch machine, suitable for this purpose, is shown and described in my prior Patent No. 1,466,903, dated Feb. 4:, 1923, this type of switch machine being operated bypower from a battery, or similar source of current, located in the tower or control oflice, over two normal and reverse control wires and a common. It is assumed that the switch machine SM will be of this type and will have normal and reverse operating wires MlV and RW, and a common return wire C. The same type of construction of switch machine may be operated by power supplied to it locally from power distribution wires, and controlled over a polarized circuit comprising two wires, in the manner shown and described, for example, in the application of C. S. Bushnell, Ser. No. 408,991, filed November 22, 1929.

The switch machine SM is equipped with suitable point detector contacts, controlled in accordance with the position of the switch points and the locked or unlocked condition of the switch machine. These point detec' tor contacts may be of any suitable construction, such as shown and described, for example, in the patent to C. S. Bushnell, No. 1,517,263, November 25, 1914. In the accompanying drawings these point detector contacts are shown conventionally and are connected by wiresd and 5 to a polarized relay SS located in the tower. These point detector contacts act, in the u al way, tamiliar to those skilled in the art deenergize the relay SS, when the switch SW is unlocked or in mid-stroke, and to energize said relay SS with current of one polarity or the other, when the switch is locked up in the corresponding position. This relay SS, whenever energized, closes its neutral contact 6, and posit-ions its polar contact 7 in accordance with the position of the switch points.

The detector track relay T, individually or in combination with other track relays,

provides suitable approach and detector locking. As typical or representative of such control, the track relay T is shown in the drawings as controlling a repeater relay TP in the tower over a circuit readily traced from indicating a connection to one terminal of a battery or other suitable source of current, through the front contact 8 of the track relay T, line wire 9, relay T]? to indicating a connection to the other terminal of said battery.

The operation of the switch machine SM and the indications of the signals 1 and 2 are manually controlled by control appara tus in the tower or control office. In accordance with this invention, this control apparatus comprises power-operated controller units, one for each switch and each signal, and small hand switches, keys, push buttons, or the like for controlling the power operation of these control units. These power-operated controller units correspond in effect to the manually operated levers now employed; and for illustrative purposes, these controller units have been shown as having the structural characteristics of the usual hand operated lever. It should be understood, however, that these controller units need not be constructed in accordance with the practice for hand operated levers, but may have any suitable arrangement or construction or parts capable of performing the desired functions. These controller units for the switch and signals, except for the arrangement of contacts and other accessories, are alike; and a description of one will sufiice for all.

Referring to the diagrammatic showing in the accompanying drawings, the controller unit LSlV for a switch comprises a slide 10, having therein a cam slot 11 for operatin the usual roller on the upper end of the usual tappet bar 12 of the mechanical locking. This slide is suitably connected, as indicated by dash lines, to circuit controller blocks 13 and 1 1-, cooperating with pairs of Contact springs as 15, in the usual way to control the switch machine SM. The slide 10 is connected by a pivoted link 16 to a crank 17, fixed to a main gear 18, the end of the link 16 being curved and engaging fixed stops 19 at or slightly beyond dead center. Connected to the shaft 20 (indicated by dash lines) of the main gear 18, is a circuit controller cam 21, having an insulated cam projection which is adapted to engage controllers on spring contact fingers 22 and 23, and move these contact fingers into and out of engagement with cooperating stationary contacts, indicated conventionally by arrows, in the two extreme operation positions oi the main gear 18. i The main gear 18 is operated by a suitable electric motor M, having an armature 2-1 and two field coils or windings 25 and 26. The armature 24 or" this motor M is connected to the main gear through a suitable friction clutch 27, and suitable reduction gearing indicated as av pinion 28.

The control units for the signals 1 and 2 are of a similar construction, but are provided with only one contact block, such as and 31.

The power-operated switch and signal controller units, above described, and associated devices, such as the relays SS and TP, are preferably located in accordance with this invention in a locked compartment or room. to which access may be had only by a maintainer or other authorized person, the various control units, relays, and connecting wires being so arranged and supported as to give ready access of all of the parts for inspection and maintenance.

The control machine which is manipulated by the operator is conveniently located in another room or ofiice. This control machine comprises, in addition to the usual track diagram and indicating lamps, a miniature lever,-or the like, for each switch and signal. As diagrammatically illustrated on the accompanying drawings, the miniature lever STVL, governing the operation of the switch machine controller unit LSlV, comprises a crank-like handle 32, movable back and forth to normal and reverse positions. Connected to this handle in any suitable way (indicated by dash lines) is a contact engaging stationary contacts, indicated by arrows, in the normal and reverse positions of the handle. The miniature levers SG'L for controlling the signals are illustrated as being ot a like construc n, but may be arranged in any other desired way. It should be understood that the various miniature levers for controlling the switches and signals of the plant are preferably located relatively close together and are so grouped that they may be all readily manipulated by the operator.

An indicator lamp 34, lighted by the voltage drop across a resistance 35, is preferably associated with each miniature lever, so as to indicate the operation of the corresponding controller unit.

To explain the operation of the system of this invention, assume that the operator desired to change the switch SW from the reverse position shown to the normal position, and clear the signal 1, permitting the train to move over the switch in this normal position. The operator shifts the miniature switch control lever SVVL from the reverse position shown to the normal position; and if the detector track circuit is not occupied, or the equivalent approach locking is not effective, so that the relay TP is energized, an operating circuit for the motor M of the switch controller unit LSl V is established and may be traced from through the front contact 36 of relay TP, wire 37, resistance 35, wire 38, contact 33 of the lever SWL in the normal or dotted line position, wire 39, contact finger 23, wire 40, motor field winding 26, wire 41, motor armature 24, to

This operating circuit through the field winding 26 of the motor causes the motor to drive the main gear 18 clockwise, and the connecting link 16 shifts the slide 10 to the right, thereby moving the contact blocks 13 and 14 into engagement with the other pairs of contact springs to establish a normal operating circuit for the switch machine SM.

If the slides 10 of the controller units for the switches and signals governing conflictihg routes are not in proper position, the usual mechanical interlocking between these slides prevents movement of the tappet bar 12 for the controller unit SLW, so that the motor M is not able to move the slide. In this case, the friction clutch 27 slips. The flow of the operating current to the motor M over the circuit just described through the resistance 35 lights the lamp 34; and if this lamp remains lighted for a time longor than required for the normal operation of the controller unit to occur, the operator is advised of this abnormal operation, and may shift his lever SVVL to avoidinjury to the motor or friction clutch.

If the operator has properly manipulated the control machine, so that the slide 10 of the switch controller unit SLVV can be moved to the reverse position, the circuit ciiiitroller cam 21 opens the contact finger 23 and cuts oil current from the motor. The crank 17 is against the stop 19, at or just beyond the dead center position, and holds the slide 10 in its operated position. In

this connection, it should be understood that, if desired, the motor M may be provided with a suitable electrically released brake, in series with the armature of the motor,

such as shown and described, for example, in my prior application, Ser. No. 399,547, filed Qctober 14, 1929.

Having thus operated the switch SW, the operator may move the miniature signal lever, controlling the signal controller unit LS1 for the signal 1, which is operated in the same way to shift the contact block 31 into engagement with the pairs of contact springs 42; and since the operation of the switch machine SM has actuated the point detector contacts PD to reverse the polarity of the energizing current for the relay SS and cause its polar contact 7 to assume the other dotted line position, a circuit for energizing the signal relay 1H is established and may be traced from through the front contact 6 of the relay SS,

wire 43, front contact 7 of relay SS, wire 44, contact block 30 and contact springs 42, wire 45, relay 1H, wire 46, front contact 47 of track relay T, and thence through such other controls forthe signal 1, indicated conventionally at 48, as may be required, to

If the operator should by mistake move the wrong signal control lever, and try to clear the signal 2, such improper clearing of the signal would be prevented, first-because the controller unit LS2 for that sig nal could not be operated, due to the mechanical locking between it and the switch controller unit LSW, and also because, with the switch Sl/V in the normal position, the

contacts of the relay SS are not in the proper position to complete a circuit through the relay 2H controlling the signal 2.

From this explanation of one typical instance of how a switch and signal may be controlled and operated, the principles and mode of operation of a complete interlocle' mg system in accordance w th this invengoverning train movements over a given switch, are governed by the contacts of the corresponding relay SS in such a way that the signal indications must conform'to the positions of the switch points. The mechanical interlocking between the controller units for signals of conflicting routes prevents operation of these units to positions which will give conflictlng slgnal lndications; and also,

if desired, the control circuits for these con-' an electric motor. In this modified construction, the slide 10 is pivotally connected to a piston rod 50, carrying a piston 51 which has an air-tight fit in a cylinder 02. The supply of compressed air to the ends of the ,cylinder 52, on opposite faces of the piston 51, is controlled by two electro-pneumatic valves EPV of the same construction.

Each one of these electro-pneumatic valves EPV comprises the usual operating coil 53, core 54, valve rod 55, double-acting valve 56 of the poppet type, and a spring 57 tending to move the valve 56 to the upper position shown. \Vhen the coil is energized and the core 54 attracted downward in opposition to the spring 57, compressed air supplied at 58 is conducted past the upper valve 56 through passage 59 to the corresponding end of the cylinder 52; and when the coil 53 is deenergized, and the valve 56 is raised by the spring 57 to the upper position. shown, this supply of pressure is cutoif, and the passage 59 is connected past the lower valve 56 to the exhaust port 60.

The energization of the coils 53 of the two electro-pneumatic valves EPV is controlled by the contacts of the switch control lever SlVL. A projection 61 on the piston rod 50, carrying insulated striking pieces, opens pairs of spring contacts 62 and, 63 in the corresponding extreme positions of this piston and the slide 10. Thesespring con tacts 62 and 63 are in series with the coils 53 of the corresponding electro-pneumatic valves, so that the coil 53 for each electropneumatic valve is automatically deenergized, after the slide 10 has been operatedv to the corresponding extreme position, the circuits for accomplishing this being readily; traced on the drawings.

An interlocking system constructed and organized in accordance with this invention may be more quickly and eficiently manipulated by an operator, since the miniature levers, which the operator shifts to different 3 positions, may be grouped together for con-' venientmanipulation, independently of the arrangement or relative location of the power-operated controller units, which may ire organized as at present in relative loca-' tions best suited to the mechanical interlocking, the track layout, or the like. These miniature levers may also be located relativelyclose-together, so that the levers for a large plant can all be in convenient reach of the operator. Also, these miniature levers may be easily and quickly shifted by the operator without the effort sometimes required to move the levers of the usual interlocking machine; andthe miniature lever for each switch and signal responds to manual manipulation in the same way irrespective of the mechanical locking. The lever latches, indication mechanism, and lever locks, commonly associated with the levers of the ordinary interlocking machine, are eliminated in the system of this invention; and the desired approach and detector locking is obtained in a simple and directway by governing the application of power to the controller unit for a switch, as illustrated by the relay TP. Other characteristic features and advantages of the system of this invention will be readily understood by those skilled in the art without detail explanation.

The specific construction and arrangement of parts and circuits shown and described are merely illustrative of the nature of the invention; and various adaptations, modifications, and additions may be made in this particular embodiment, without departing from the invention.

lVhat I claim is 1. In a power interlocking system, the combination with a power-operated track switch and signals governing train movement over said switch, power-operated control devices for said switch and signals, mechanicalinterlocking between said control devices, and manually operable levers one for each control device for governing the power operation of said control devices individually.

2. In a power interlocking system, the combination with a power-operated track switch and signals governing train movement over said switch, circuit controller units for governing the operation of said switch and signals and including an electric motor, mechanical interlocking between said units, anl means including manually operable circuit controllers for governing the operation of the electric motors of said units individually.

3. In a power interlocking system, the combination with a power-operated track switch and signals governing train movement over said switch, a controller unit for said switch and each of said signals comprising a circuit controller and a slidable member, mechanical interlocking interconnecting said slidable member, an electric motor for moving each slidable member to either of two extreme positions, and means including a manually operable circuitocontroller for controlling the operation of each motor.

4. A system of power interlocking comprising, circuit controller units movable to either of two extreme positions for governing the operation of switches and signals, mechanical interlocking between said units, a power device for moving each unit, a manually operable circuit controller for each power device for governing the supply of power to each of said devices, and track circuit controlled means for at times modifying the operation of said power units in response to said manually operable circuit controllers.

5. In an interlocking system of the type described, power operated circuit controller units for go erning the power operation of a track switch, other power operated circuit controller units for governing the indications of signals controlling train movements over said switch, mechanical interlocking between said controller units, a relay adjacent said first mentioned controller units and having contacts positioned in accordance with the position of said switch, signals governing traffic over the switch, and control circuits for said signals including the contacts of said signal controller units and contacts of said relay.

6. In a system of the type described, the combination with power-operated track switches and signals governing train movement over said switches, a power-operated circuit controller unit for each switch and signal, mechanical interlocking between said controller units, manually operable means for governing the power operation of said units individually, and means associated with each unit for indicating when power is applied to the corresponding unit.

7. In a system of the type described, the combination with a power-operated trafiic controlling device, of a circuit controller unit for governing the operation of said device, an electric motor for actuating said circuit controller unit, a manually operable switch and control circuits for supplying current to said motor, and indicating means responsive to such supply of current.

8. In a system of the type described, the combination with a plurality of power-operated controller units for governing track switches and signals, mechanical interlocking between said units, and means comprising an electric motor and friction clutch for each unit for operating such unit unless such operation is prevented by the mechanical interlocking.

9. A power interlocking system comprising a plurality of controller units connected by mechanical interlocking for governing the operation of switches and signals, and remote controlled power operated means one for each unit for operating said controller units individually by power.

10. In combination, an office, an interlocking plant including a plurality of tralfic controlling devices, levers at said plant, one for each of said devices, mechanical interlocking means for interlocking said levers against mal-operation, a separate electrically operated power unit for each lever for operating the same, and a control lever at said c-tlice for each of said power operated units for controlling said units.

11. In combination, an oflice, an interlocking plant including a plurality of trafiic controlling devices, levers at said plant, one for each of said devices, mechanical interlocking means for interlocking said levers against Illill-OPBI'ltiOIl, a separate electrically operated power unit for each lever for operating the same, a control lever at said office for each of said power operated units for controlling said units, and track circuit controlled means for modifying the control of said power operated units by said control levers.

In testimony whereof I alfix my signature.

WINTHROP K. HOWE. 

